Telephone system.



B. D. WALLIS.

TELEPHONE SYSTEM.

APPLxcAHoN FILED Nov.28, 191s.

Patented Feb. 4, 1919.

2 SHEETS-SHEET l- B. D. WMS.

TELEPHONE SYSTEM. APPLICATION FILED NGV-28,1913. LQQS' atented EdwinF919.

2 SHEETS-SHEE 2.

. distinguish `provelnents in BERNARD I). WILLIS, OF CHICAG, ILLINOS,

erfreut Tien im @il hitler..

ASSEGNOR BO AUTOMATXC 'ELECTRC COMPANY, 0F CHICAGO, ILL'LNOXS, ACGBEORATGN OF XL1-IN OES.

TELEPHONE SYSTEM.

Specieziton. of Letterslatent. lrerrtt, iii-Elli,

Application filed November 2S, lt. Serial No. 363,581.

To all whom. t may concern:

Bc it known that L' BERNARD D. illinois, e citizen of the United Statesof America, and resident of Chicago, Cook county. illinois, haveinvented eerteilnnew and useful lm- Telephone Systems, o which thefollowing-'is a specification.

My invent-ion relates to improvements in telephone systems, und `moreparticularly to automatic or semi-automatic s vstems-thnt is, systems inwhich n connection 'is eslablished in whole or in part through theinedium of automatic switches.

One oi' the lfeatures of my invention relates to gsystem employing lineswitches controlled by n muster switch for selecting: idle trunks. nsuch system l provide meansjor preventing two or more subscribers whohave removed their receivers from the swit'chfhooks while the masterswitch is rota-ting tofi'nove the line switches of a groin.;

lopposite en idle trunk from connecting with 4the seme trunk after themaster switch stops.

Furthermore, I provide menusiwnerehy.y ii two 0r more subscribers haveremoved their receivers from the switch-hooks whileithe master switch isrotating, the line switches on these subscribers lines will connect withseperate trunks.

A. further feature ot my invention is the provision of means for givingen operator in n semi-automatic or manual system o. discriminating lousytest-that is, enable her to between n lousy test obtained from testingthe multiple jack of the cuiling sulbscrihers line which is connected tothe answering'end of the ope ntors cord in cuit, and a. busy testobtained from 'testing` the jack of some other suhscrihers line.

A further feature of my invention is the rovision otmproved ineens fordiscormecting the ringing current from the celled suhscribers line asSoon as the called subscriber removes his receiver from the hoch. Herenfore', when the ringing current was intern mittently applied, thiscurrent. could only he disconnected during the interrupt-ions oi' theringing current. By my invention, howeverj the ringing;r Current isdisconnected immedintely upon the response of the celled suhscriber,regardless of whether or not the ringing current is ut that timecomici-ted with the line.

These und other objects of my invention will he more readily understoodhy refer-- ence to the accompanying drawings, in which .i have.illustratedL one embodiment oi my invention in connection with nsemieutomstic system employing line switches of n well-known typo und nnoperntorls cord circuit.

Figures l and :Z teiten rtogether show n complete circuit connectionbetween n 'culling substation A. und :1- cnlled substation A ein--hodyinff` the principles of my invention. The connection is completedthrough the medium oi the individual switch C. cord circuit 0 und theculled subscriber-s individunl switch C" to the substation A.

Fig. 3 shows n modified forni ,of cord cir-- enit.

Referring to l? the line f 'onduetors 30 and 'Si of the su lierssulostution ter .urinate in the individuell or line switch C. ",lfheline switch shown et C is one of e. group o'l similar line switches theplungers (not shown) of which engage u shnift nud ure controlled hy theoperntion or' the nmster switch shown :it in such u munner th-.it theyure. when in not-nml position. held directly in ltrout of the terminalsof n trunk line lending` to :in idle cord circuit i?. The cord circuit lis equipped with the uceessni'v nppurutus i'or completing connectionwith :my one of :t plurnlity of rsuhstntions (only one of which isshown) connected to the line Conductors 3'3 und 322 iihg. 2) through themedium oi the limL `switch C. Although there is shown only onesubstation A connected to the line conductors -l und 3?). it wiii heunderstood that n plurnlity ei" like suhstntions muy he connected to theseid lines. Thejringers ot the dili'erent substations muy lir'".\rrangedin muy well-known manner to respond to the ringing current generated 'bysome purtieulnr oncot n. plurzillty o' generators.

The subscribers substation A. is of any suitable or uppioved type undcomprises the usnnl receiver 2., trunsmittcr ZBw switch-hook i, ringeL 5and condenser l. The line een" ductors ci 'ih-e su'nl sul/slut:-termiimtc in the central exchange iu :.1 lil.` 'witch .ic cannluetms:rmi with tho indivi unl swim (i is the mul-.linie jut-lr j. throughwhich vor ,ttions :irc es; tended to the suhstutior; A.

rlfhe prinnu'y line switch C is or the grenger su Wis imma?" sprl! milfsRH muy, 315cm is mmm:

he shzfnfifia" :513.

'is operated. y rlnglng circuit 1s a relay so constructed switches towhich the line switch C belongs. The relay `59 is energized whenever itscor responding trunk 1s 1n use, Vhcn all the v trunks leading from saidgroup become busy at one time, and therefore all the relays 59encrgizech the relays 60 and G1 become energized over the .followingcircuit: 'from ground. Gr'15 through the Contact of springs 62 of eachtrunk relay 59 and through the said relays GO and 61 to battery' Therelay 607 upon energizing, removes battery from the-pull-in windings ciall the line switches oi this xgroup. The relay 61, upon energizing',opens the circuit of the start relay G3 of the. master switch DL so thatsaid master switch `will not operate until a trunk line becomes idle.

The trunk line seized by the switch C terminates in the cord circuit 0,through the medium of which the circuit is completed to the called line.The tivo ends ot' the cord circuits are connected together through themedium of the condensers it and 45. The cord circuit is also providedwith the usual calling` 'and answering supervisory signals 47 and t6 andthe necessary relays for controlling the saine. The relay 48 is a groupbusying signal, 2'-, e., it is a relay to make all trunks to anoperators position busy as long as there is an uncompleted 4co11.inction at said operators position. The relajtlll may be common to all thecord circuits of an operators position. The meter M is the means forregistering all calls handled by one opera-tor. The reays 49, 50 andv 51furnish means for giving a discriminating busy test whereby the operatorcanx ascertain "whether she is testing a multiple jack of the callingline con-- nected tothe answering end of the cord, or of some other busyline; Multipled through the springs 55 and 56 and 55 and 56 ot everycord circuit common to an opcrators position there is a conductor 541-,the function of which is to prevent the operators head set P beingconnected to more than one cord circuit at a time, if it so happenedthat more than one call was successful in reaching an operators positionat one time. he keys KQ K2, K3 and Ki are the means by which any one ofa plurality of generators (only one shown) may be connected to the cordcircuit O for signaling purposes. The said .keys are so arranged thatwhen any one of vthese keys, is depressed, any other depressed key willbe mechanically restored to normal, so as not to allow two generators tobe connected to the conductors -52 and at one time. The connection oi'the ringing current to the called line is controlled by the ringingrelay 112, which' is energized when any one. of the keys K', K2, K3 orK* Connected in series with the and adjusted that it will notoperatively energize when ringing' current from the generator ll. istransmitted through it to the called substation and through thecondenser at the called substation to ground` but the instant thereceiver is removed at'the culled substation and the substation talking'set is bridged across the line, the said relay 5S will receive sulicientcurrent through the battery B in series with the generator 'll tooperatively. energize.

The line switch C and the substation A are sinlilar in all respects tothcliine switchl C and the substation The cord circuit L' (Fig. 3) issimilar to the cord circuit O except that the ringing of the calledsubstation is started automatically by the operator plugging into themultiple jack of the called substation.

Havinglgiven a general description of the apparatus involved in thesystem, in order to give a complete understanding of my invention itwill be described how the subscriber at the substation A. may obtainconnection with the subscriber at the substation A. When the rcceiveratthe substation A is removed from the switch-hook preparatory to making acall, the engagement of the hook-switch springs completes abridge acrossthe line through the receiver and transmitter of the substation. Theclosurel of this bridge across the line establishes an energizingcircuit for the line relay 14@ of the. line switch C. The relay 14, uponenergizing, operates to close the circuit of the operating Winding 12 ofthe magnet 11, which, upon energizing, attracts 'the plunger arni- 10and the cut-off armature 16, whereby the line `conductors 30' and 3l areextended through the line switch bank springs 17 and 2l and 2O andv2l tothe cord circuit O, and the line relay 14 is disconnected from the line.`When the connection is extended to the said cord circuit O, the linerelay 64, which is normally bridged across the line circuit of the cordO in series with the battery7 becomes energized Iand operates to closethe circuit of the holding Winding; .l3nt the line switch C before theline relay 1s denergizes. It also operates to close the circuit et thetrunk relay 59. The circuit for the holding winding' 13 of the switch Cextends 'from ground G2 through the relay con t or springs 67 and 66 ofthe relay 64e, bare., springs' 22 and '1S and the said holding winding13 to battery By. The circuit for the relay S9 extends over the samecircuit as .tar as the bank springs 22 and from there it passes throughthe relay 59 to battery B. A guarding ground potential is also suppliedto the bush 68 of the multiple jack j to make the calling line testbusy. The closing of the bank springs 19 and 23 causes the master switchD to operate in a well-known manner to move the plungers of all the idleline switches oppositec'the next idle trunk line. A further result ofthe enersprings 122 and The key l locks in its depressed position(holding the contact or springs 11/1 closed, but allowing the springs115 to close and then separate) and mechanically restores the keypreviously operated to normal. The rela)y 112 is energized as soon asthe key l is depressed and operates toelose a locking circuit for itselfthrough 'the springs 11o independentot the springs 115 at the key l. Thesaid locking circuit extends from ground G5 through the contact ot'springs T3 and 101 ot the relay 91, lsprings 117 of the relay 5S.springs 11o and the said relay 112 to battery A further result or' thecnergization ol the relay 11.2 is to disconnect the calling line fromthe called line and to connect the generator to the called lino over thefollowing pata: from ground (lo tlnough the coil 118, Contact or springs119 and 120,

.rinfy contact oli' the lu f o. sirinrf 121 of ls .s

the Jack j, 'conductor 97 to and through the substation fr', conductor96, tip si'ning5 of the1jack j, tip of the plug p', springs ano 123,relay springs 111i; of the key n', springs 124 and (when the.interrupter relayv127 is denergized) and the generator R through thebattery ll to ground G. The 129 and the springs 12() and 128 are shuntedby a very high resistance, or by a very sinall condenser. This allows avery small portion ot the ringing; current to be transmitted backthrough the calling line to the calling substation, thus. giving'thecalling subscriber an audible ringing signal, informing bini tliattliecalled subscriber is being signaled. il have `found that the highresistance may bc merely aline drawn by a carbon pencil on the.insulatingr mounting between. the said- Clpriugs, or the condenser maybe the capac ell'ect of a pair of insulated vgires twisted together, onewire electrically connected to one spring and the otlierwire connectedto the other spring. Either gives very satisfactory results. rlhecalled. subscriber is signaled intermittently through the medium ot''the interrupter 140 and the interrupter relay 127. Should the calledsubscriber answer during the ringing period, the bridging` of thesubstation talking set across the line would cause the relay 58- toreceive sutiioient current through the bat.- tery and generator inseriesto operatively energize. 4The relay 58, upon energizing, opens thelocking` circuit of the relay 112 at the springs 117. The relay 112,upon deencrgizing, disconnects the generator troni the called line,connects the calling line With thc/called line-over the heavyconductors shown and bridges the relay 13,1 ,across the calledline. Therelay 131, 'upon energizing, opens the circuit cgt the supervisory lamp47 at the springs 132. Should the called subscriber answer during' thetime that the interrupter relay 127 is energized, the rela-y 58 wouldreceive euiiicient current through the coil 130 to operatively energizeand perform the saine operations as above described.

The replacing of the receivers at the called and calling' substationssignifies to the operator that the conversation is terminated. Vvhen thereceiver at the substation A is restored to the switch-hook, theseparation of the'hook springs destroys the energizing circuit of theline relay Gl. The relay (il, upon denergizing, causes the supervisorylamp 16 to glow over the following circuit: from ground (il through thespringsI 73 and 101, springs 133 and 7S) and the said lamp to battery B.rllie replacing of the receiver at the called substation A opens thecircuit of the relayY 131. The relay 131,'upon denergizingj, closes acircuit through the suporvisory lamp 47 over the following path:

-trom ground G" through the springs 73 and 101, springs 13:5 and thesaid lamp to battery B. The operator, upon receiving the disconnectsignal, removes the plug pI from the jack j', thus breaking the circuitof the relay 91 and the lnidge-cut-oll' winding Sli of the line switcht". The relay 91, upon denergizing, opens the circuit-s ofnthe relays 99and 65re1noves'the holding '.'round from the holding winding 13 of theline switch C and opens tlieclrcuits of the supervisory lamps do and 17.The holding windingof the line sWitclrC, upon denergizing, allowstheline switch plunger to be returned to normal. 'The relay 99 ispreferably made slow acting so that t-he line switch C is givensuiiicie-nt time to return to noi'- rnal before the private conductor104 iS again connected 'to the group busying relay common to the variousother cord circuits.

The cord circuit L (Fig. as hereinbe fore stated, is similar to the cordcircuit O, with the exception that the ringing,r is startedautomatically and not by means of a key. When a connection isestablished between the substation A and a called substation not shown,which may be similar to the substathe operation of the line switch C andthe cord circuit L is the same as for ythe liz o switch C and the cordcircuit O up to the time when the operator plugs the plug p2 into themultiple jack of the called substr tion. Vhen this operation takesplace, the relay 135 energizes, as hereinbefore stated, with the saineresults as before described and with the additional result of causingthe relay 134 to energize, which, in the previous cord circuit, wasenergized by the pressing ol' the key K. The energizing circuit for therelay 134 extends from ground G through the contact of springs 13Gl and137, springs 139a and 138 and the said relay 134: to .batt-ery B. Therelay 134, upon energizbe ore described and. locks itself up over a.tion A, by means of this cord circuit L,

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512011 that hu devi. d Yei'y GGL menus; for giving the o! wlmi i. diffng busy feste wher )y she mm (libu minimi-aim the busy tesi obtainedfx'mil time miiilips; i( uf n line winmx-ted m fihi n cmi u wird undduit 0b fram testing 5mm other jme. iii: ha; c iiiustiiitfsii :imi isixiffivi'isw'f'f lim :i iiiw switch individua mi mi,

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controlling said magnet to con-ncct said line with any one ot' saidtrunk lines. :1 second line, a second progressively movable trunkingswitch for said second linc. an operating magnet for said second switch,a second liuc relay t'or controlling said second operating` magnet, andan energizing circuitI for said second operating.,r magnet-under thecontrol ot' said first relay.

9. ln a telephone systemq a calling line` :i called line, a lilikcircuit for connecting the two, aplug for extending a connection fromthe link to the called line, a. source et signaling current., a signaltor the called line, a circuit for applyingsaid current to said calledline to operate said signal, a relay for controlling said circuit to'control thc operation of said signal, a second relay in series withsaid source of current in said circuit, said first relay controlled bysaid second relay, which operated in turn over said circuit. while thesaidsignal is being operated, and a relay for intermittent-lyinterrupting the said circuit.

10. In antelephone system, a calling line, a called line, a, switch forconnecting said lines, a signal for the' called line, a circuit.comprising a ringing,r current generator and a battery, another'circuit/comprising said battery and a. resistance, a relay foralternately connecting said circuits in series with a slow acting relayiand a third relay for connecting said slow acting relay and circuitswith the called -line to periodically operate said signal, said thirdrelay controlled by said slow acting relay 1l@ In a #telephone system, arst line, a second line, and a third line, talking conwitch for eaclline, a relay for each switch, an operating magnet for each switch,means tor operating one ci said relays over one el the talking"conductors of its line, first to Control its associated operatingmagnetto connect ,its line with another ol. said lines and second to renderthe operating magnets ofV the other of said switches inoperative. y l2.In a. telephone system, a i'irst line, a second line, a third line, aswitch for each line, a relay foreach swiwli, an operating magnet foreach switch, a circuit :for escl?. Eii'iagnet controlled by itsassociated relay7 means for'energizing' said relays simultaneouslywhereby the rst of relays may operate its associated operating magno-ttoextend a connection to another, line, `and means whereby said -rst eyrentlers` the controllingcircuit ier the-'operating magnets of saidvother switchesf'inoperative.

1.3111 a telephone system, a, first line,l a second line, a third line,a switch tot' each line, e. relay for each switch, an operating n'gnetfor each switch,` acircuit 'for each magnet controlled. by itsassociated relay,

5D' ,means for energizing; said relays simultane- ,sev l? ously wherebycach of said relays may control tlic circuit ot' its associated magnetto cxtcnd a connection to another line, and-may also control the circuitof the operating inagnct of thefnext succeeding switch whereby saidlines may be successively connected to other lines.

ll. ln a telephone system, a first line, a'

second line, a third line, an automatic switch t'or each line, a relaytor each switch, an operating magnet tor eachk switch, a circuit foreach magnet controlled by its associated rcla means for energizing saidrelays simultaneously whcrebythe tirst of said relays may operate itsassociated operating magnet' to extend a connection to another line, andmeans whereby said first relay renders the controlling circuit for theoperating magnets ol said other switches inoperative.

l5. in a telephone system, a first line, a secoml'line, a third line, al'irogressively movablc switch for each line, a relay for each switch,an operating magnet for each switch, a circuit 't'or each magnet-fcontrolled by its associated relay, means toi-,energizing said relayssimultaneously whereby the first of ing magnet to extend a connection toanother line, and means whereby said first relay renders the controllingcircuit for the operating magnets of said other switches inoperative.

lo. In s, telephone system, a first line,V a second line, a third line,an automatic switch for each line, a relay for eac-h switch, anoperating magnet for each switch, a circuit for each magnet controlledby its associated relay,`nieans for energizing said relayssimultaneously whereby each oiE said relays may control the circuit ofits associated magnet to extend a connection to another line, and mayalso control. the circuit ot' the operating niagnet. of the nextSucceeding switch whereby said lines may be successively connected toother lines.

17. ln telephone system, a iirst line, second line, a third line, aprogressively movable switch 'tor each line, a relay for each switch, anoperating magnet for each switch,

said relays may operate its associated operas circuit for each magnetcontrolled by .its

associated relay5 means for energizing said relays simultaneouslywhereby each of Said relays may control the circuitoif 'its naso? elatedmagneti' 'to extend a, connection .to an,- other line, and may alsocont-rol the :circuit ol? the operatingy magnet of tbe-next. suer switchwhereby sai individual 'to lsaid first line for rendering the controlcircuit of the second lineA inoperative when the said rst line makes acall to the third line, a signal for said third line, a source ofsignaling current, means for intermittently applyin'gvsignaling currentto the line to operate said signal, and means for aitomaticallydisconnecting said signaling current from the line as soon as the calledsubscriber responds While the `signil .10 is being operated.

Signed by meet Chicago, Cook county, Illinois, this 20th day ofNovember, 1913.

- BERNARD D. WILLIS.

Witnesses:

H. W KRACKE, Amon OSWALD.

